  .text
  .globl main
main:
  addi  $s3, $zero, 21
  addi  $s4, $zero, 42
  bne   $s3, $s4, Else
  add   $s0, $s1, $s2
  j     Exit
Else:
  sub   $s0, $s1, $s2
Exit:
  jr    $ra
